Rotary pump



E. ZEFP ROTARY PUMP Dec. 18, 1956 4 Sheets-Sheet l Filed Dec.

NVENWP EM/L Z E PP 4 Sheets-Sheet 2 E. ZEPP ROTARY PUMP Dec. 18, 1956 Filed Dec. s, 1952 E. ZEPP ROTARY PUMP Dec., 18, 1956 4 shawls-sheet s Filed Dec. s, 1952 5 vrs/vm@ EM/L ZEPP E. ZEPF ROTARY PUMP Dec. 18, 1956 4 Sheets-Sheet 4 Filed Dec. 3, 1952 INVENTOR EMIL ZEPP..

ATTORNEY.

Untfi States PatentV AVV1 ROTARY PUlVIP The present invention "relates to a rotary pump for gases and liquids. Y

Conventional rotary pumpsare very large when built for producing, greatpressure or suction andare particularly unpractical'in'cases in which the amount'of gas or liquid to be pumped is small relatively to the pressure tobe produced. Such pumps must be over-dimensioned and their power consumption is too great for economic operation. yRotary piston pumps are capable of deliver-V ing small amounts of gas'or liquid vat great pressure and suction heads. -Such pumps, however, wear out quickly and their use ,is limited.

vIt is an object of the present invention to provide a rotary pump capable of delivering small amounts of gas or liquid at great pressure or suction heads, which pump is small and which is no more subject to wear than conventional centrifugal pumps.

Y tion and claims, and shown in the drawing which, by way.

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of illustration, shows what I now consider to be preferred embodimentsof my invention.

In the drawing: Fig. l is a schematic illustration of a three-stage pump e according to the invention showing a development of the stationary annular inlet and ouelt conduits and of the4 impeller buckets;

Fig; 2 is a diagrammatic longitudinal section of `a three-stage pump according to the invention;

Fig. 3 is a diagrammatic longitudinal section of a modified three-stage pump according to the invention;

Fig. 4 is a perspective view into the interior of the pump according to the invention with the irnpellers removed.

Like parts are designated by like numerals in all gures K of the drawing.

As seen in Fig. l, the ilow area of the annular inlet conduits or channels 1 diminishes like a wedge along the inlet of the impeller wheels provided with blades 5 having leading edges lEi and trailing edges 5V in theV same manner as the iiow area of the annular outlet conduits or channels 2 increases like a wedge along the outlet of the impeller wheels. The ow area of the annular outlet conduits 2 is greatest at the point of transition into the following annular inlet conduit l. The radial l a valve effect between the wheel buckets and the conduitsl The pump according to the invention comprises pump i wheels designed for axial flow and receiving the matter to be pumped from and delivering it vinto annular c o' axially'V arranged channelsor conduits whichlare wedgeshaped n'circumferential direction. The inlet and outlet conduitsvare preferably in axially symmetrically opposed position and so dimensioned that the total circumferential Y ow areas of the ,two conduitsis the same at all radial sections of the two conduits'. Overlapping of the ends thepump wheels is oi advantage. e

Whereasvpconventional centrifugal pumps are usually sodesigned that they require a minimum of operating power when Yclosed and a maximum when open, the operating characteristic of the pump accordingV to the invention is opposite, i. e. its power consumption is smallest in open condition and greatest in closed condition. Though the pump according to the invention is rotary, its operating characteristic is that of a reciprocating pump. It closes the gap left by conventional rotary pumps for cases requiring great pressure or suction heads and small amounts of gas or liquid to be delivered and in which wear is objecn'onable. f

The number of buckets of the wheels or impellers of the new pump is preferably proportionate to the pressure to be produced. The buckets are preferably at a right angle to the adjacent stationary annular inlet and outlet conduits. The suction or leading edges of the blades of the rotors are preferably bent in the direction of the circular travel of the blades. Cylindrical axial extensions may be provided at the outer diameter of the hubs of neighboring impeller wheels of a pump according to the invention so that a continuous cylindrical part is formed between the hubs of neighboring wheels, which part forms the inner wall of the stationary annular conduits between the impeller wheels.

walls or connected outlet and inlet conduits have overlapping end portions 4 which are parallel to the planes in whicl'il the leading and the trailing edges of the blades 5 are located. The short overlapping portions 4 produce l yand 2. This effect controls the hydraulic efficiency of the pump, andthe clearance between the portions 4 and the wheels should therefore be as small as possible.

The' pump operates as follows:

The air, gas, or liquidin the annular yinlet conduits 1 formed by wall portions 14 assumes the same shape as the wedge-shaped annular conduits and is continuously milled oli on one side of the wedge by the impeller wheel blades 5 which act like a milling cutter; the relatively low pressure at the inlet side of each pump wheel pulls onthe'me'dium in the inlet channels. oil parts of` the .medium areV accelerated and pressed through' Ythe buckets intoA the Vannular outlet conduits 2j in` which kinetic energy of the accelerated medium is transformed into pressure, causing the medium to how into the following inlet conduit or channel l, whereupon the process is repeated. The inlet or leading edge portions 5 of the blades 5 forming the wheel buckets are bent in the direction of the circular travel of the blades as seen in Fig. l. The main portions of the blades 5 are at a substantially right angle to the wall portions 14 forming the conduit l. The solid line arrows in Fig. l indicate .the direction of ow of the pumped medium. The dotted line arrows Vin Fig. l indicate the direction of rotation of the blades 5.

As shown in Fig. 2, impeller wheels 3 individually Y comprising a wheel body or hub portion 9 having` a pe- The outer surfaces of the hub extension-may be threaded, singly or multiply,

in a direction opposite to that of the fiow of the medium 'Y ripheral portion l5 and blades 5 extending substantially radially therefromarey mounted on a shaft 6 between annular inlet and outlet conduits l and 2, respectively,

which are formed in the cylindrical pump casing by means lof spiral-shaped interior wall portions 14. The

wall portions 14 are individually opposed to ythe leading edges '.5' and to the trailing edges 5 of the blades 5 and are individually wound aroundl the rotation axis of the shaft 6 in helixes whose generatrices are at a right angle tothe Ycylindrical'inside surface vof the pump' casing.' l'

The casing comprises end portions or covers 7 and 7' and intermediate portions 8. The illustrated pump j has three stages, each stage having one pump wheel. By increasing the number of wheels and intermediate'por- 2,774,307` Patented Dec.Y 18, 19756 v Themillcd l' VvcontinuousY and solid cylindrical wheelV body.

tions 8', any desired number of Vstages may be produced.

Thewheel bodies or hub portions 9 and blades-5 may' be produced separately. VAA motor 11 may be mounted f o n a lantern ltprovided onpthe end portion fl.

1 Wheresn Fia-2Y the individual wheelseraser? arzated "or spaced by suitablestationaryV portions of the intermediate parts S, they may be separated ,by'gcy'iiul Y drical portionsror extensions 12 of the peripheral por-V parts S'Yiseparating the conduits 1 and 2 extend as closely as possible Vtowardrthe extensions i2 sothat the annular clearances '13 between tnewall portions 14',anlthre'ex-V tensionsZ are yYsrnall. VInorderto reduce Vthe losses caused' by the' Vclearances 13,*ithe outer'surface offthe 'f extensions' '12 is threaded, the h and of.the` threads'l Y' generatrices are at a right angle to the'inten'or surface 1 of said cylindrical Wall portion `for forming alt channel and an outlet channel for the medium pumped by said pump wheel. u

2. A rotary pump as defined Yin claim 1 in which said s blades are at a substantially right angle to said-interiorV wall portions.Y V

3. A rotary pumpw'accordring; to claim 2 in which the Y end portions of.l said blades 4which YportionsV include ,thej

leading edgesV of the blades arebent in 'the Vdirectiorr'of rotation of said blades.'` i Y y 1 @i 4. A rotarylpump forl gases uand forlquids compris-V ing aV rotatable'shafL-a plurality j'of fpunp wheels; eachl being opposite ltorthat ofV therhelixfes in which the interior- Wall portions 14' are Wound around the'shafnt 6. VThe threads onft'jne extensions i2 tend to return gas or'liquid Y escaping through the clearances 13.

Whilel believe the above described embodimentsV of' Y Y my'invention to Vbey preferred embodiments, I Wish it to be: understood that I do not desire to be limited to the exact details of design and construction shown and described, for obvious modications will occur to a person skilled 'in the art. Y Y

What is claimed is: Y Y Y v `1. A rotary pump'for gases and forl liquids cornprising a rotatable shaft, Va pump wheel having a huo Vportion mounted on said shaft and having a peripheral portion, a'plurality'of blades Vmounted on' and extending f outwardly from said peripheral portion substantially,

Aradially of the rotation Vaxis. of saidr shaft and aiording joW of theVv medium to he Vpumped inra gdirectionV sub-v stantially parallelV to the rotation` axis offsaid shaft; VsaidV blades havingY leading edges positioned inv'anfimagi-'l n narypiane whichis ata right'angle to tllerotation".axisk n of'said shaft, said bladeshaving trailing edges`positioned i' j inian imaginary plane which is atY aright angle to theV rotation axis of said shaftandpsvpaced from the plane` in whichxsarid leadingV edgesY'aregp'ositioned,V and a pump casing surrounding Vsaid pump" Wheel, Y*said* Vcasing *havingV gaV Ycylindrical outerwall,A portion 'Whose'. interior' surfacev Yis adiacenti@ Said blades,V said` easing having Vinteri' r .vvall portionsvindivi'dually opposed to :said leading edges and to .said .trailing1V edges and .being individually Wound.' Y around the rotation',V axis of said shaftvinrhelixesu'whose/ of 'said Wheelsvhavinga hubportion mounted on'sid shaft and having Ya peripheral portion, a plurality 'of blades mounted -on- 'andextending'outwardly from said Y Yperipheral portionA substantially radially'of the rotation 1 1 axis of saidshaft andaifording oyvof the. rnediuinVA to be pumped inYaldirectionjsubstantially. parallelf'ltofg rotation axisV offsaid'shafvtfjfsaid blad/esL havinggleading edges positioned in'anY imaginaryplanewhihisatea; Vrighta'ngle'to the rotationftaxis of said shaft;Vsaidjblades: having trailing edges-positioned in'an ,imaginaryV planet which is atV alight angle to the rotationaxisof said;V shaft .and spaced from` the'lplane in which-said leading; edges are positioned,Y land a pumpcasing surroundingL said l pump wheels,'said casing havingY a Vcylindrical outer Walli v v portion Whose interior surface is adjacent to said blades,-`

said casing having interior Wallportions opposedto's'aidleading edgesjand Vtoy said trailing edges and beingwindividually- Wound around the rotation axisof said shaftfinY helixeswhose generatrices areat a right fanglel'rtfoY theY interior'rsurface ofsaidrcylindricalfwall portion forjformf Ling inlet channels yand Voutlet channels forlthe mediumf pumpedby said Wheels, the jperipheral portions offsaid tion Aagainst eachother.

Whose-hand isV oppositetoV that of the'helixesinvvhrich; saidinterior wall portions are Wound around 'said shaft 1,378,891V Musrswirztrn,

. hub portions,beingcylindrical and'abutting in axial direc?, Y Y 

